In recent years, technological advancements have continually pushed the limits as to how fast data can be transmitted between two points over twisted pair copper lines. Currently, data transmission rates of 56 kilobits per second (Kbps) are achievable using voice band analog modems commercially available today. For establishing internet protocol (IP) connectivity, these systems use point-to-point protocol (PPP) or serial line internet protocol (SLIP) for transmitting internet protocol (IP) packets over serial lines. In accordance with PPP or SLIP, data is transmitted between two computers via respective modems connected to each of the computers and operating a compatible modulation scheme. In this configuration, each bit of data received by one of the modems causes an interrupt to be generated at the receiving computer in order to notify the computer the bit of information is available for processing.
A relatively new data transmission technology referred to as digital subscriber line (DSL) is capable of providing data transmission rates of 1 to 9 megabits per second (Mbps) over twisted pair copper lines. This technology is particularly attractive, especially with regard to internet service access, in that it instantly increases the transmission rates by two orders of magnitude over the transmission rates currently available over twisted pair copper lines. Furthermore, since twisted pair copper lines have long been used to provide telephone services in the United States and throughout the world, they are already in place, interconnecting most homes and businesses both within the United States and around the world. Other technologies which can presumably provide equal or even greater transmission rates typically require the deployment of a transport medium such as optical fiber, as proposed in fiber-to-the-curb (FTTC) or fiber-to-the-home (FTTH) systems. Such an effort is costly and takes a very long time to implement, particularly in rural areas.
Examples of specific DSL technologies include asymmetric DSL (ADSL), high-bit-rate DSL (HDSL), and rate-adaptive DSL (RADSL). In accordance with DSL technology, one DSL modem is placed at the customer premise and a second DSL modem is placed at the central office of a local exchange carrier. The DSL modem at the central office will most likely be in a modem pool for servicing multiple customers at a time, though each second modem is dedicated to a particular customer, that is, a particular first modem. The maximum data rate achievable in this configuration will depend upon numerous factors such as the wire gauge, noise, cross-talk, distance between the DSL modems, and the type modulation utilized. At the central office, the DSL modems are connected to an access node that provides an interface between the second DSL modem and a local area network (LAN), a wide-area network (WAN), or some other service system for providing services such as internet access, interactive videos, video conferencing, etc. In the interest of brevity, a detailed explanation of DSL technology will not be provided here since DSL technology is known in the art.
However, with the substantial improvement in transmission rates provided by DSL technology, most personal computers in use today are not able to process the amount of data transmitted between two DSL modems without causing a data overflow problem. Consequently, transport protocols other than PPP or SLIP have been proposed for use at the central office in order to connect the customer premise computer(s) to the access node at the central office. For instance, ethernet/IP (hereinafter referred to as ethernet) and asynchronous transfer mode (ATM) are two such transport protocols. These transport protocols provide for packet switching which only generates an interrupt to a host computer at the arrival of each packet rather than at the arrival of each bit of data. This substantially reduces the number of interrupts generated, and thereby, dramatically reduces the processing time taken to process the received data.
In the case of ethernet, a typical configuration comprises one ethernet LAN at the customer premise and another ethernet LAN at the central office.
However, it would be desirable to enable a single computer at the customer premise to access the ethernet LAN at the central office without having to go through an ethernet LAN at the customer premise.
Thus, a heretofore unaddressed need exists in the industry for interfacing a computer at a customer premise with an ethernet LAN at a central office, wherein the customer premise and central office are interconnected by a DSL link.